Download Designing an Electron Gun for an Electrostatic Accelerator Phillip Lloyd, Mark Yuly

Designing an Electron Gun for an
Electrostatic Accelerator
Phillip Lloyd, Mark Yuly
Houghton College
Department of Physics
What is an Electrostatic
Accelerator?
The Electrostatic Accelerator at
Houghton College
High Voltage
Terminal
Target
Accelerating
Column
SimIon Modelling Software
Laplace's Equation
Gauss's Law
∇ ∙ E = ρ/ε0
∇ ∙ E = -∇ ∙ ∇ V = -∇2 V
Electrostatic System: Laplace's Equation
∇2 V = 0
∇2 V = -∇ ∙ E = -dEx/dx – dEy/dy – dEz/dz
One Dimension
d2V/dx2 = 0
V = ax + b
Approximation
V = (V1 + V2 + V3 + V4)/4
V1
V2
V
V4
V3
Designing an Electron Gun
Electron Gun: Early Designs
Control
Grid
Outer Shell
Acceleration Grids
-770 V
Source
-1000 V
0V
0V
-1002 V
Focusing
Grid
0V
Electron Gun: Later Designs
Base
-1015 V
0V
-980 V
0V
Source
-1000 V
Control
Grid
Focusing
Grid
-1000 V
Acceleration Grids
Outer Shell
0V
Electron Gun: Current Design
Control
Grid
Shield
Acceleration Grids
Base
Source
-500 V
-460 V
-380 V
0V
-350 V
Focusing
Grid
0V
Outer Shell
0V
Simulations
Actual Construction
Deflection Plates
Acceleration Grids
Focusing
Grid
Control
Grid
Shield
Source
Testing the Gun
Testing the Gun
Conclusion

Overview
We need an electron gun for our electrostatic
accelerator
By building our own, we can easily repair and
modify the gun as needed
We can model and simulate gun designs in SimIon
SimIon has its limits, and physical testing is
necessary to finalize a design